Hydraulic control apparatus

ABSTRACT

A hydraulic control apparatus comprising a plurality of standard multiple function conduit modules adapted to be selectively programmed in various arrays to effect substantially any required hydraulic control functions. The apparatus is further characterized by leakage collection zones at the interfaces of adjacent modules and a common drain passage through said adjacent modules.

12/1969 Keller et al. 285/137 R X o United States Patent [191 [111 3,794,066 Raymond '8 Feb. 26, 1974 [54] HYDRAULIC CONTROL APPARATUS 3,589,387 6/1971 Raymond 137/271 [75] Inventor:' Robert E. Raymond, Zanesville, FOREIGN PATENTS OR APPLICATIONS 01110 564,280 7/1958 Belgium 285/13 [73] Assignee: International Basic Economy C o New York, NY, 1 Primary Examiner-Martin P. Schwadron Assistant Examiner-Richard Gerard [22] led: 1971 Attorney, Agent, or Firm-Palmer Fultz 211 App]. No.: 213,314 v v [57] ABSTRACT 52 us. CI. 137/312, 29/1571; 29/407, A hydrauliC control apparatus comprising a plurality I 29 4 9 235 4 of standard multiple function conduit modules 51 1111. c1..; F16k 11/10 adapted to be selectively programmed in various [53] Fi ld of S h 137 312; 2 5 13 14; 29 4 9 rays to effect substantially any required hydraulic control functions. The apparatus is further characterized [5 References Cited by leakage collection zones at the interfaces of adja- UNITED STATES PATENTS cent modules and a common drain passage throug 3,144,035 /1964 I-Iablanian et al 285/13 x Sald adjacent modules 3,4 $5,5l6

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ATTOR EYS HYDRAULIC CONTROL APPARATUS This invention relates generally to hydraulic apparatus and more particularly to fluid power control systems adapted to be fabricated from a plurality of multiple function of standardized components.

In the fabrication of hydraulic control systems, such as power packages for the industrial field as well as for pump, motor, and control valve assemblies for mobile equipment, military applications and other uses where controlled fluid power systems are required,- it has been the practice in the art to fabricate the control systems from various control valves and associated components that are connected in circuit by external piping.

ln other instances, it is a practice in the art to join together such valves and components in contiguous relationship so as to eliminate some external piping by bolting together housings of individual components such that the ports in one housing connect directly with the ports of the next adjacent housings of the system. This approach has resulted in the elimination of certain external piping but the applications have been specialized and have consisted of custom built housings and bases constructed for theparticular application without any provision for standardization and interchangeability of multiple function modular components. Such conventional hydraulic control systems which inherently require a plurality of individual control valves for performing different control functions have traditionally associated together various valves of both standard and specially designed construction, with the result that each,of the individual control valves has been incorporated in the overall control system as a separate species constructed of its own respective specialized valve components.

ln accordance with the present invention, a unique system is provided for fabricating substantially any fluid power control system to perform substantially any control function, both simple and sophisticated, from a plurality of multiple function standardized circuitforming block components of modules without the use of major interconnecting piping conduits.

There is always the possibility that high pressure seals in fluid systems can leak for a variety of reasons and this basic problem, of course, is present in the conduit system of the present invention where high pressure seals must be used at the various joined interfaces of standardized conduit and valve modules. Some of these reasons are imperfections in seals or mating surfaces, deterioration of seals, etc. Moreover, the more seals, the higher the probability of some leakage. In addition, it is not generally defensible to assume absolute no drop'isealing in direct high pressure interface seals.

In accordance with the present invention, a unique arrangement of double seals with drain between which insures that any high pressure leakage past an inner high pressure seal is collected and prevented from leaking through a second low pressure seal where the problem of secondary leakage is negligible, since such second seal is only required to seal against atmosphere or very low pressure.

As a primary aspect of the present invention, the standard modules are uniquely joined at each block interface and each valve interface so as to include a drain region external to the normal high pressure seals for the duct junctions at the interfaces. Such drain region is connected by standard passages in the modules which are in turn connected automatically by the junction of blocks and valves into a common drain passage which communicate throughout the entire assembly and lead to an external port connected to reservoir or some leakage receptacle.

As another aspect of the present invention, the novel sealing arrangement discussed above is uniquely adapted for application to a modular conduit system that incorporates circuit-forming modules that are all uniquely arranged to include what will be termed herein a dual duct 4 port" configuration which can be arranged and programmed with standardization to selectively provide series, parallel and series-parallel hydraulic circuitry applications.

As another aspect of the present invention, the novel sealing arrangement discussed above is uniquely adapted for application to a modular conduit system that incorporates multiple function basic control valve modules of standardized construction, including a multiple function spool valve element, which can be applied to the above mentioned system in a variety of selectively programmed modulating and switching configurations so as to provide a varietyof control functions, as well as a variety of structural arrays such that virtually any simple or complex hydraulic control application can be achieved from standardized multiple function valving modules.

As another aspect of the present invention, the novel sealing arrangement discussed above is uniquely adapted for application to a modular conduit system that incorporates standardized multiple function circuit-forming modules that are adapted to co-operate in a unique way with the above mentioned multiple function valving module so as to permit the fabrication of substantially any composite hydraulic control system from a relatively small inventory of standardized multiple purpose blocks or modules of simple, inexpensive design.

As another aspect of the present invention, the novel sealing arrangement discussed above is uniquely adapted for application to a modular conduit system that incorporates a standardized center block module adapted to register and co-operate wtih parallel side block modules in an infinite variety of arrays with said center block module providing the multiple function of a mounting means for the selected valving module and also the junction for a plurality of outwardly extending side arm assemblies of the above mentioned standardized conduit modules. It will be understood that with this arrangement, various different control and circuitforming functions can be respectively provided by the outwardly extending side arm assemblies with the switching of flow between the side arm assemblies being affected by the above mentioned center block and associated valve module so as to accomplish any selected interbranch valving function. Moreover, and most important, any or all of the above mentioned side arm assemblies can in turn be arranged to communicate with additional center blocks and thereby deliver a switches or controlled flow to a next successive valving module on the additional center block so as to vary, amplify or refine the flow. It will now be understood that various control flows can be divided, combined, modulated, amplified and treated in various ways merely by the use of the standardized circuit-forming modules and valve modules defined above.

As still another aspect of the present invention, the novel sealing arrangement discussed above is uniquely adapted for application to a modular conduit system that incorporates all of the above mentioned center block, side block and bus block modules, as well as spacer block modules adapted for use therewith, which are structurally standardized to the extent that their ultimate three dimensional assembly into an array of standard valve controlled branches can be accurately, schematically depicted on a two dimensional schematic drawing or flow strip such that even the more complex flow paths as well as the valving functions performed thereon can be easily designed and readily understood. This permits a hydraulic technician with ordinary skill to readily program a selected control system on a two dimension flow diagram in a manner that he can readily select the necessary standard valve modules required for the particular application. It should be emphasized that it is only by the overall standardization of all of the various components described above, that such simplification of a three dimensional apparatus to a two dimensional flow strip can be realized.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

IN THE DRAWINGS FIG. 1 illustrates a typical fluid power control system constructed in accordance with the present invention;

FIG. 2 is a diagrammatic view showing the flow circuit of the hydraulic control apparatus of FIG. 1;

FIG. 3 represents a flow strip display of the schematic flow circuit represented in the hydraulic control system of FIG. 2. This flow circuit of FIG. 3 is functionally the same as that shown in FIG. 2, but has been transposed into the flow strip form so as to show a dual duct passage arrangement of the various modules and components of FIG. 1. Such modules and components of FIG. I are each illustrated by dotted delineation in FIG. 3;

FIG. 4 illustrates the total assembly of conduit modules that provide the dual duct flow paths in the typical hydraulic control system of FIG. 1. Here the valve modules, control modules and fastening rods have been removed;

FIG. 5 is a partial exploded view of a first assembly comprising a portion of the control system of FIG. 1;

FIG. 6 is a partial view, partially in section, of a portion of the first branch assembly of FIG. 5;

FIG. 7 is an exploded view illustrating a second branch assembly comprising another portion of the control system of FIG. 1;

FIG. 7-A is a plan view of a typical gasket comprising a portion of the assemblies of the preceding figures;

FIG. 8 is an exploded view illustrating a bus assembly comprising another portion of the control system of FIG. 1;

FIGS. 9 and 10 are top and end elevational views of a bus block comprising one of the modules of the typical control system of FIG. 1;

FIGS. 11, 12 and 13 are top, side and end elevational views of a bus block adapter that comprises another module of the system of FIG. 1;

FIGS. 14 and l4-A are side and bottom elevational views of a parallel side block, P1 P2, comprising another module of the system of FIG. 1;

FIGS. 15 and l5-A are side and bottom elevational views of a second parallel side block, PI P3, comprising another module of the system of FIG. 1;

FIGS. 16 and 17 are top and end elevational views of a one-third standard spacer block comprising another module of the system of FIG. 1;

FIGS. 18 and 18-A are side and bottom elevational views of a parallel side block, P2 P3, comprising another module of the system of FIG. 1;

FIGS. 19 and 19-A are side and bottom elevational views of a parallel side block (three-way Pl P2 P3) comprising another module of the system of FIG. 1;

FIGS. 20 and 21 are top and end elevational views of a series side block comprising another module of the system of FIG. 1;

FIGS. 22 and 23 are top and side elevational views of a four-way valve adapter block comprising another module of the system of FIG. 1;

FIGS. 24 and 25 are top and side elevational views of a filter adapter block comprising another module of the system of FIG. 1;

FIGS. 26, 27 and 28 are end, side and opposite end elevational views of a center block module of the system of FIG. 1;

FIGS. 29 and 30 are top and end elevational views of a full standard spacer block comprising a module of the system of FIG. 1;

FIGS. 31 and 32 are top and sideelevational views of a modified one-third standard spacer block comprising a module of the system of FIG. 1;

FIGS. 33 36 are elevational views of a direct spring bias cross relief valve comprising a version of the valve module of the system of the present invention; and

FIG. 37 is a diagrammatic view of a novel sealing arrangement constructed in accordance with the present invention.

Referring in detail to the drawings, a typical fluid power control system is indicated generally at 20 in FIG. 1 and is constructed from conduit and valve modules provided with common interface characteristics, such as seals, rods, ports, between the conduit modules. These blocks are divided into important functional categories later to be described in detail herein. In general, the blocks are arranged in a typical bus assembly 42, FIGS. 1, 3 and 8, which provide dual duct conduits for the pressure and flow from a centralized source of pressurized fluid such as a variable volume pump 66 illustrated in FIG. 2 as well as for flow back to a reservoir 74. Such dual duct arrangement consists of a pressurized duct which is connected to pump 66 and a drain duct 112 is connected to reservoir 74.

It will not be seen that bus assembly 42 and the ducts 110 and 112 provide pressure and drain for two branch assemblies of dual duct conduit modules, a first branch being indicated generally at and the second branch being indicated generally at 132. Each of the branches coming from the bus ducts 110 and 112 represents a complete manifold assembly for operating specific fluid motor functions. For branch 130, a typical rotary type motor load is indicated at 108, FIG. 2, and for branch 132 the power cylinder 106 of FIG. 2 represents a typical load.

First branch 130 is mounted on bus assembly 42 by a bus adapter block 34 directly connected to a center block 30. A parallel side block 26 is mounted on the top face of center block 30 and in turn serves to mount a second parallel side block 22. The entire branch assembly 130 is fastened to bus block 36 of bus assembly 42 by mounting bolts 146 extended through holes 151 in base flanges on bus adapter block 34 and into threaded holes 153 in the top surface of bus block 36.

It should be mentioned that interface seals for the dual duct functions between the branch and bus modules are provided by a standard T-seal construction seen at 120 in FIGS. 5 and 6. The duct 134 and 136 of first branch 130, FIG. 1, lead to the fluid motor 108 as seen in FIGS. 2 and 3. Here will be seen the outlet ports for such ducts 134 and 136 are in the top interface of parallel side block 22 as seen at 134l-A and 136-A.

In accordance with the primary aspect of the present invention, the above mentioned interface seals 120 comprise the inner high pressure seals of a unique arrangement of double seals with drain between which insures that any high pressure leakage past an inner high pressure seal is collected and prevented from leaking through a second low pressure seal where the problem of secondary leakage is negligible since such second seal is only required to seal against atmosphere or very low pressure.

Such novel sealing arrangement is diagrammatically illustrated in FIG. 37 and by the supplemented FIGS. 6, 7, and 7-A which illustrate the application of a typical gasket 143. Typical modules 8 and 10 include typical interfaces 3 and 5, the above mentioned high pressure duct seal 120 and an outer low pressure seal 143 which may be formed of any suitable gasket materials. When the modules are drawn togehter by the rods 114, FIG. 6, the presence of outer seal 143, which may be approximately, for example, 0.010 inch thick, maintains interfaces 3 and 5 separated slightly to form a low pressure leakage collecting zone 6 between the two seals I and 143.

It will further be seen from FIG. 37 that the gasket or outer seal M3 also maintains the relatively high pressure zone 4 with off-set 6 forming the annular shoulders for the pressure extrusion type of high pressure seal I20.

With continued reference to FIG. 37, a typical leakage drain passage is shown in typical module 10 and throughout the drawings of the modules such leakage drain passages are indicated by the same numeral.

Reference is next made to second branch assembly 132, FIGS. 1-4 and 7, mounted on bus assembly 42 by a bus adapter block 78. A center block 80 has its lower face mounted on bus adapter block 78 and the upper face of the center block supports a one-third spacer block 96 and parallel side block 98 as is best seen in FIG. 7. Also, a side face 149 of center block 80 mounts two one-third spacer blocks 84 and 86 as well as a parallel side block 88.

The entire branch assemblies 130 and 132 are each mounted on bus assembly 42 by bolts 146 that extend through holes 151 through base flanges on bus adapter blocks 34 and 78.

Referring again to FIGS. 1 4, power cylinder 106 is connectd to duct 140 at outlet port 140-A. Conduits I38 and 142 are provided with plugs 91 and 93 in the final assembly sincethese conduit ports are not utilized in the particular typical control system.

Referring particularly to FIGS. 1, 4 and 8, bus assembly 62 comprises standard modules comprising bus blocks 36, parallel side block 44, full standard spacers 50 and 52, bus block 54, full standard spacer 56 and series side block 58, all bolted together by standard manifold rods 122 of the required length. Also manifold rods are used for securing together the modules of the branches as seen at 114. The bus rods 122 extend through all of the bus modules and are secured at each end by rod nuts 118. Hence it will be seen that the standard rods provide means for connecting together any selected branch or bus assembly of conduit modules and performs the compression on the interface between the conduit modules and seals 120 for the standard dual duct system. The interface seal construction 120 is also illustrated in FIG. 5, an exploded view of branch 130 and these seals are provided at each interface junction between conduit blocks.

FIG. 8 illustrates an exploded perspective view of bus assembly 42 which also utilizes the standard seals 120 at the abutting interfaces of the bus modules.

The rods 122 that are used to assemble the bus modules are of the same diameter and include the same thread characteristics as the rods 114 that are used to mount the various modules to the center blocks 30 and in the branch assemblies 130 and 132, the only difference being that the rods 114 that mount to the center blocks actually thread into tapped holes 155 in the center blocks and secure the side blocks and other modules to the center blocks, whereas the rods 122 that mount the bus modules together extend through the entire bus assembly and their threaded ends are provided with standard manifold rod nuts 118. Also, fastening rods 114 and 122 are provided with flats, not illustrated, adjacent their threaded ends to permit gripping the rods with a wrench when the rods are screwed into female threaded members and tightened.

It should further be pointed out that the relative lengths of the conduit modules in the direction of the dual ducts, such as ducts and 112, are as follows, assuming a standard arbitrary module length X:

Module Relative Length 1. Bus Block 36-54 2X 2. Bus Adapter 34-78 IX 3. Parallel Side Block Pl-PZ, 22-36-44-88 IX 4. Parallel Side Block PI-P3, 98 IX 5. Parallel Side Block P2-P3, FIG. I8 IX 6. Parallel Side Block Pl-P2-P3, FIG. 19 IX 7. One-Third Standard Spacer (Through) 86 A X 8. One-Third Standard Spacer (l Duct Blocked) 84 vs X 9. Full Standard Spacer, 50-52-56 1X 10. Series Side Block 58 2X 1]. Center Block 80-30 Terminal Block for Rod Ends (any appropriate length) The standard fastening rods length 114 and 122 and the module lengths represented by X and whole and fractional multiples of X in the above table are all established to be multiples of a standard arbitrary module length whereby a relatively few standard rods can be selectively used to secure together various selected combinations of modules.

It will now be understood that the dual duct arrangement which is of a specific diameter and specific space orientation throughout the entire conduit block apparatus is maintained constant throughout the system. For instance, the conduit spacing, size and seal arrangement in the branch assemblies and 132 are exactly the same as the corresponding characteristics in the bus assembly.

All blocks mounted to center blocks, such as center blocks 30 and 80 in FIG. 1, are identical in their interface characteristics with the result that any block which is positioned at any location in the entire system can be selectively mounted at any other location in the control system for interchangeability and universally common characteristics.

In general, another important novel feature of the standard dual duct principle is that the dual ducts in the branch assemblies, such as 130 and 132, are adapted for the mounting of standard power flow valve modules which are mounted on standard center block modules 30 and 80. This arrangement permits diverting or switching flow from the main dual ducts to any required porting in the sides of the center blocks. Such side porting and the valve passages in turn function as dual duct conduits and hence directional flow control is performed by a center block and valve combination such that the flow from a center block module to other modules in the branch assembly is determined by the switching characteristics of the particular direction valve mounted on the center block. When the flow is switched to the side faces of the center block, it is always returned to the dual duct passages of the conduit modules with the flexibility of being able to program various types of modulating and flow switching valves to effect whatever flow or directional characteristics are required for the particular control system.

Reference is next made to FIG. 3 which is a flow strip diagram, depicted in two dimension, single plane arrangement for simplicity of analysis of the three dimensional array that forms the control system of FIG. 1. Here it is easy to trace the flow of fluid from the pressure source, hydraulic pump 66, through the entire in tegrated manifold assembly which delivers controlled flow to the typical loads provided by rotary fluid motor 108 and power cylinder 106. A pressurized bus duct 110 connects pump 66 at an inlet port 110-A to the hydraulic control apparatus 20 and a low pressure bus duct 112 returns flow to reservoir 74 via outlet port 112-A of the control apparatus. Hence the flow proceeds through bus block assembly 42 in a standard dual duct arrangement that services the two branch assemblies 130 and 132 previously described.

As seen in FIG. 3, the flow entering pressurized bus duct 110 via inlet port 110-A proceeds through a series side block module 58, full standard spacer 56, and then to a first bus block 54. At that point, pressurized flow is diverted to pressurized branch duct 138 by a bus adapter block 78 to a center block 80 of branch assembly 132. At center block 80 the flow is switched by a four-way directional valve 82 which is illustrated mounted on a face of center block 80. In operation, the flow is switched from an internal pressurized passage 150 of four-way directional valve 82 to an outlet passage 152 and proceeds through branch duct 138 of one-third standard spacer module 96 located in a side arm circuit of branch 132. The flow from one-third standard spacer module 96 proceeds into a parallel side block 98 which mounts a pressure compensated flow control valve module 100 and a reverse check plate module 120. The flow then proceeds by series type through valve module 100 into branch duct 140 and port 140-A leading to power cylinder 106. With this type of flow through pressure compensated flow control valve 100 to duct 140, it will be seen that the flow is blocked by an obstruction 158 in duct 140 located in one of the duct forming portions of one-third standard spacer 96.

It will now be seen that the original dual duct flow in branch 132 is converted to single duct flow to power cylinder 106 by obstruction 158. As the pressurized flow is directed into the rod end of power cylinder 106 via duct 140, discharge flow from the other end of power cylinder 106 is delivered via port 144-A and returned to a side arm assembly on center block which side arm includes one-third standard spacers 84 and 86 and parallel side block 83, FIGS. 1, 3 and 4.

Side block 88 mounts a standard power flow valve module programmed as a counter-blance valve 90, which maintains back pressure on power cylinder 106 responsive to a control adjuster 92 and a check valve 94 which provides a blocked flow condition in the direction from power cylinder 106 back to center block 80. The flow from line 144 and side arm duct 161, FIG. 3, passes through counter-balance valve to the other side arm duct 142. At this point it should be pointed out that there is an obstruction 160 to duct 144, said obstruction being located in one-third spacer 84. This prevents return flow from line 144 from being delivered back to the center block via passage 156. Return flow must therefore in reverse such that thhe discharge flow returns through branch duct 140 in parallel side block 198 to pressure compensated flow control valve and the reverse check valve module 102 to branch duct 138 and leading to passage 152 of four-way valve 82. The valve connects passage 152 to passage 156 and flow passes via ducts 140 and 112 to return line filter 62 and bypass relief 64 in series side block 58 and back to reservoir 74.

In summary, the entire branch assembly 132 provides a control function in which four-way valve 82, mounted on center block 80, performs a switching function for the pressure and return flows from bus assembly 42 to power cylinder 106 accomplishing pressure and flow control of such cylinder and its load in a precise and definite manner through the entire conduit module assembly of branch 132.

With continued reference to FIG. 3, the flow to and through first branch assembly will next be described. The same pressurized bus duct 110 that supplies the branch 132, just described, flows through full standard spacer modules 52 and 50 proceed through passage 142 back to the passage 154 of fourway valve 82 at center block 80. it should be mentioned that when four-way valve 82 was switched so that passage 150 was connected to 152, passage 154 is also connected to passage 156 by the same action of the four-way valve. Therefore the return flow proceeds from passage 154 to passage 156 and branch duct leading to low pressure bus duct 112. At this point the return flow is directed through a return line filter 62 or a return line bypass relief valve 64 and then via line 112 to reservoir 74. Here an obstruction 166 in series side block 58 prevents a short circuit flow to reservoir around the filter 62 and bypass relief valve 64.

With continued reference to the flow arrangement for branch assembly 132, FIGS. 2 and 3, it will be understood that if pressure delivered to line of fourway valve 82 had been diverted to output passage 154 and passage 152 of said valve 82 had been connected to passage 156 by the action of four-way valve 82, then the reverse flow to power cylinder 106 is delivered via passage 142 and check valve 94 in counter-balance valve 88 in a dual duct arrangement and power cylinder 106 is thereby operated and parallel side block 44 to bus block 36. Parallel flow is normally maintained in the two bus ducts 110 and 112 of parallel side block 

1. A conduit system for a fluid power control apparatus fabricated from a plurality of standardized conduit modules that can be assembled in a plurality of arrays at standardized conduit interfaces having standardized conduit ports, said conduit system comprising a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at an interface, and an outer low pressure seal in spaced surrounding relationship with said inner seal at said interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said interface that communicates with said zone and a common drain passage through said adjacent modules.
 2. The apparatus defined in claim 1 that includes a valve module provided with a valve interface and ports that connect with said valve interface and port of a conduit module at said seals to form said leakage collecting zone.
 3. A conduit system for a fluid power control apparatus fabricated from a plurality of standardized conduit modules that can be assembled in a plurality of arrays at standardized conduit interfaces having standardized conduit port configuration and provided with a plurality of selected external valving arrangements, at least one of said conduit modules including three interfaces having said standardized port configuration that provide a three-dimensional array of power flow branches; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal in spaced surrounding relationship with said inner seal at said one interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules.
 4. A conduit system for a fluid power control apparatus comprising, in combination, a plurality of standardized conduit modules forming conduit ducts and having standardized conduit port configuration that can be assembled in a plurality of arrays, said modules including means for selectively assembling either parallel flow hydraulic circuits or series flow hydraulic circuits, said circuits being selectively formed by only two main power flow ducts common to the modules; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal in spaced surrounding relationship with said inner seal at said one interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules.
 5. The conduit system defined in claim 4 wherein said selected circuits are either parallel flow between two ducts or series flow in a single duct.
 6. The conduit system defined in claim 4 wherein said selected series or parallel flow circuits can be selectively arranged between modules and ducts as may be required for the requirements of the system.
 7. The conduit system defined in claim 4 wherein said means comprises standardized duct interrupting conduit modules including said standardized conduit port configuration.
 8. A fluid power control apparatus fabricated from a plurality of multiple function standardized modules forming conduit ducts and having standardized conduit port configuration, said apparatus comprising, in combination, a standard conduit module including first and second interfaces provided with said standard port configuration, two main duct forming passages extending between said interfaces for the power flow of the system, and a third interface, power flow ports connectable within said conduit module with said two main duct forming passages; a power flow valve module including a standard mounting and port interface having ports communicating with said ports in said third interface of said conduit module; means for selectively either interrupting or opening one of said duct-forming passages to selectively program parallel, series, and series-parallel power flow circuit connections between said valve module and said ducts; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal in spaced surrounding relationship with said inner seal at said one interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules.
 9. A hydraulic control system comprising, in combination, a plurality of conduit modules provided with interfaces having standardized conduit port configuration and forming a bus assembly including a pressurized bus duct communicating with a source of pressurized fluid and a fluid return bus duct communicating with reservoir; a second plurality of conduit modules forming a branch assembly including first and second branch ducts communicating with said bus ducts, said branch assembly comprising a standard conduit module provided with first and second interfaces and including standard port configuration joined to interfaces of adjacent conduit modules in said branch that includes said standard port configuration, and a third valve mounting interface; valve means mounted on said third valve mounting interface of said conduit module, said conduit module including first passage means leading from said ducts to said valve and second passage means leading from said valve back to said ducts; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal in spaced surrounding relationship with said inner seal at said one interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules.
 10. A fluid power control apparatus comprising, in combination, a plurality of standardized modular components joined together at interfaces provided with interfaces having standardized conduit port configuration, each of said components including a plurality of pasSages having ports that register with ports and aligned passages in a next successive component, certain of said components including a side interface provided with said standard port configuration for the mounting of a branch assembly of said standardized modular components, said side interface including transverse passages and ports adapted to register with said first mentioned ports; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal at said one interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules.
 11. The steps in the method of constructing a hydraulic control system comprising: depicting the hydraulic flow circuit on a two-dimensional flow strip diagram of modular components adjacently positioned to form a dual duct flow system; selecting standard modules forming conduit ducts and having standardized interfaces provided with conduit port configuration adapted to be assembled in a three-dimensional flow diagram; providing an annular leakage collection zone in surrounding relationship with said conduit port configuration at each of said interfaces of the plurality of adjacent modules; assembling said modules in a three-dimensional structural array to provide said system; and draining leakage from said leakage collecting zone through a common drain passage through said adjacent modules.
 12. A conduit system for a fluid power control apparatus fabricated from a plurality of standardized conduit modules that can be assembled in a plurality of arrays and provided with a plurality of selected external valving arrangements, said conduit system comprising a first assembly of conduit modules, each of said modules including a standardized conduit interface configuration provided with ports that register with ports in the interface configuration of other modules and including main power flow passages that communicate to form main power flow ducts for the first assembly and a side interface; a second assembly of conduit modules, each of said modules including a standardized conduit interface configuration that registers with the interface configuration of other modules, and including main power flow passages to form main power flow ducts for the second assembly, certain of said conduit modules including an end interface that registers with said side interface or said first assembly for connecting the respective power flow ducts of the two assemblies, certain of said conduit modules including a side valve mounting interface provided with passages communicating with said main power flow ducts for mounting a power flow valve module, said plurality of conduit modules being structurally assembled independently of said valve module; a leakage collection zone at each of said interfaces of the plurality of adjacent modules, each of said zones including an inner high pressure seal surrounding a port at one of said interfaces, and an outer low pressure seal at said interface, the space between said two seals forming said leakage collecting zone; and drain passage means including a drain port in said one interface that communicates with said zone and a common drain passage through said adjacent modules. 